John william charles coven schirm



(No Model.)

J. W. O. O. SCHIRM. MAGNESIUM LIGHTING APPARATUS FOR TAKING -P110'I'OGRAPIIIG PICTURES.

Patented Feb. 19, 1889.

metallic magnesium when burned spreads an UNITED STATES PATE T OEEicE.

JOHN \VILLIAM CHARLES COVEN SCHIRM, OF BRESLAU, PRUSSIA, GERMANY.

MAGNESIUM LIGHTING APPARATUS FOR TAKING PHOTOGRAPHIC PICTURES.

. SPECIFICATION forming part of Letters Patent No. 398,084, dated February 19, 1889.

Application filed May 4, 1888. Serial No. 272,816. (No model) T 0 (all whom it may concern:

Be it known that I, JOHN \VILLIAM CHARLES (OVEN SCHIRM, residing at Breslau, in the Kingdom of Prussia, German Empire, have invented certain new and useful Improvements in illagnesium Lighting Apparatus for Taking Photographic Pictures, of which the following is a specification.

My invention relates to improvements in lighting apparatus for taking photographic pictures.

In rooms where daylight is scarce and in seasons when scarcely one day offers sufficient light, even for a short fraction of time, for taking photographic pictures the necessity of employing artificial light is an urgent necessity, particularly for taking photographic portraits. The magnesium light, being the best for such purpose, attracts more and more the attention of all interested in the photographic art, and the object of my invention is to provide an improved device for employing the magnesium. It is a well-known fact that the intensive white light which is particularly useful for lighting objects to be photographed where daylight fails. It is also well known that the use of magnesium, with the modes hitherto practiced of employing the same, is connected with some inconveniences whichform an obstacle to the more general application of this splendid artificial light.

Magnesium in the form of bands or strips or slips can only be obtained at a high cost, and a considerable quantity of it must be burned for taking one picture. The strips when burned develop a thick cumbersome smoke. To carry off this smoke, particular exhausting devices must be provided, and,

nevertheless, the smoke in many cases, as in closed rooms, renders impossible the use of magnesium in this form. The light produced, besides, is not so intensive as to allow a very short exposure. To overcome these difficulties, i magnesium has been employed in the form of powder, mixed up with chlorate of potash or 2 another suitable substance which supports j combustion by readily rendering oxygen. These mixtures, ignited by means of a fuse,

succeeded, indeed, in obtaining a light which,

though for a short moment only, possessed extraordinary intensity and was sufficient to take a photographic picture from persons and other objects which require only a very short exposure. This mode of using the magnesium 5 5 has been adopted nearly generally of late; but it is likewise subject to several inconveniences, which so far have not been overcome, and which. consist in the following objectionable features: First, the said mixtures dey'elop, when burned, an intensive smoke, which must be drawn off'by means of special and extensive apparatus; second, the said mixtures in the greater part are liable to eX- plosion, and are dangerous to preserve on this account; third, it has not been possible up to this time to obtain ignition of the said mixtures at any given moment at the full command of the operatolyithe moment of ignition cannot with certainty be determined sometimes the ignition totally fails or ensues at a wrong moment, so as to endanger the operator;) fourth, it has not been possible, so far, to effect ignition of the magnesium powder simultaneously at two or more different points. Accordingly, notwitlistanding all the advantages offered by this intensive momentary lighting, the heavy black shades produced bya light thrown on the object from one side only could but partly be overcome by compli- So cated and extensive reflectors.

To overcome the danger of explosion of the mixture of the magnesium powder, the said powder has been blown through a pipe and across the flame; but by this procedure the combustion is very incomplete, a considerable part of the powder passing the flame unburned and falling to the ground. The light produced, accordingly, is but little intensive. In this operation the light is spread 0 from one point only, and the dark shades could not be sufficiently overcome.

By the improvements embodied in the apparatus hereinafter described all these difficulties have been successfully obviated. 9 5

In the accompanying drawings, Figure l is a vertical central section of a Bunsen burner provided with my improvement. Fig. 2 is a similar section of a modification, showing a spirit-lamp provided with the improvement. Ioo

Fig. 3 is a sectional side view of a burner provided with my improvement in connection with an electric regulating device.

The construction of this improved apparatus is as follows:

Immediately above the air-ports of a Bunsen burner, a, Fig. 1, a tube, 0, is introduced into the tube of said burner, the tube cbeing bent upward at its forward end and provided that, on igniting the magnesium powder, suftiment light is thrown upon the said person or object and the shades are cleared as much as required. The application of two burners will in many cases be found suificient.

'lhe feed-pipes Z of the several burners are connected to each other and to a gas-supply reservoir or generator. The open ends of the upright outside portion of the tubes 0, into whicha small quantity (about 0.02 gram each) of magnesium powder has been introduced, are connected to each other by a suitable rubber pipe or other conduit in connection with a hollow rubber ball or other suitable apparatus by which a sudden blast can be produced. The Bunsen burner is then lighted. At the desired moment, the operator having prepared the photographic apparatus, and

everything being ready for exposure, such a free of any development of smoke.

n'eparations requiring only a dim daylight or candle or gas light, a sudden pressure is applied to the rubber ball, or the blast-valve is opened, and the atmospheric pressure, simultaneously entering into the pipes c of the several burners, will force the magnesium powder in a iinely-distributed jet throughout the whole length of the lmrner-flame, effecting a momentary and complete combustion of the powder, which, without any perceptible de velopment of smoke, spreads an intensive light exactly at the moment determined by the operator and at his immediate control.

In using a spirit-lamp the burner is constructed according to the modification shown in Fig. which represents a Berzelius burner.

provided with suitable valves shutting cit the pressure from each distinct apparatus, and the shut-off valves may be inclosed in an electric circuit, which by an electro-magnet or other suitable device opens the valves instantaneously and simultaneously when the circuit is closed. By this means perfect simultaneousness may be obtained in lighting the several magnesium blasts. An arrangement of this kind is shown in Fig. 3. Into the burner-tube a a bent pipe, 11 is introduced, as before described, said pipe b being connected through a rubber pipe with an air-compressor, c, the piston cl of which is forced upward by a spring which is maintained in its compressed state by an armature, e, of an electro-magnet engaging with the piston-rod. At the desired moment the operator closesthe circuit the electro-magnet attracts its armature, which releases the piston-rod, and the spring forces the piston up and causes a blast to sweep through the pipe 19 and below the magnesium powder therein contained through the flame of the burner a, where its ignition and complete combustion are eltected.

The electro-magnets of the several burners applied at a time are all inclosed within a common electrical circuit, which on being closed attracts the armatures all at a time.

Bymeans of these-improvements I obtain a perfectly dangerless combustion of the mag nesium powder, the combustion is instantaneous and complete, and an intensive light is developed and may be thrown on the object with absolute simultaneousness from different points, the moment of ignition being entirely under control of the operator. The exceedingly small quantity of the dangerless magnesium powder required for each exposure is The possibility of lighting the object of the photographic picture from different sides ata time attords a superior distribution of light and saves the expense and troublesome application of lanterns, exhaust-pipes, reflectors, igniting devices, and sundry other accessories hitherto inseparable from magnesiumlamps.

Having now particularly described and ascertained the nature of my said invention and in what manner the same is to be peri formed, I declare that what I claim is A narrow tube, 7), is introduced into said 1 burner, the outside end of said tube being bent upward to receive the magnesium powder. If two or more of these burners are applied, the open ends of the tubes 1) are connected to each other and with a blast, as bet'ore described.

'lheblast-pipe leading it'ililOSPhGl'lC pressure to each of the magnesium-pipes may be The combination of a burner, a, with a bent tube entering said burner and adapted for the reception of the magnesium, and with an air-blast pipe, substantially as specified.

In testimony whereof I hereunto sign my name, in the presence of two subscribing wit nesses, this 17th day of April, 1888.

JOHN WILLIAM CHARLES COVEN SOlIIRM.

Witnesses:

ROBERT BECKER, Hans TRENTIN. 

